A major international health study has shown that excessive mobile phone use can be linked to four different kinds of cancer.

The research, which has taken 10 years and cost £20million, found that heavy mobile users suffered up to 50 per cent more tumours.

Scientists now say there is a "significantly increased risk" of people developing three different kinds of brain tumour and one of the salivary gland. News of the findings, which are to be published within the next eight weeks, has led to calls for mobiles to carry health warnings.